This invention relates to lubrication control systems for power transmissions, and more particularly, to lube systems for rotating clutch assemblies in power transmissions.
Parallel shaft or countershaft type automatic transmissions employ a rotating multi-disc ratio clutch for each gear ratio in the transmission. Since only one ratio clutch is fully engaged during steady state transmission operation, the remaining clutches are in an open running or free running condition and therefore contribute to spin losses in the transmission. Lube oil is continually supplied to the clutches and therefore a viscous drag occurs in the open running clutches between adjacent discs which are rotating at a speed differential. The spin losses are proportional to the oil film thickness or the amount of lube flow across the discs and the speed differential.